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Unsecured Senior Notes Narrative (Details) - USD ($) $ in Thousands					3 Months Ended		9 Months Ended
		Sep. 18, 2019	Sep. 03, 2019	Jun. 21, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Repayments of Unsecured Debt							$ 699,237	$ 0
Loss from early extinguishment of debt					$ 28,010	$ 0	28,010	0
Proceeds from unsecured senior notes							1,548,106	0
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Repayments of Unsecured Debt							699,237	0
Loss from early extinguishment of debt					28,010	$ 0	28,010	0
Proceeds from unsecured senior notes							1,548,106	$ 0
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					8,450,000		$ 8,450,000
Debt Instrument, Covenant Description							The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50 and (4) an unencumbered asset value of not less than 150% of unsecured debt.
Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.505% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross				$ 850,000	$ 850,000		$ 850,000
Senior Notes Pricing				99.815%
Debt Instrument, Interest Rate, Stated Percentage				3.40%	3.40%		3.40%
Debt Instrument, Interest Rate, Effective Percentage	[1]			3.505%	3.505%		3.505%
Proceeds from unsecured senior notes				$ 841,400
Boston Properties Limited Partnership | Senior Notes [Member] | 10.5 Year Unsecured Senior Notes 2.984% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 700,000		$ 700,000		$ 700,000
Senior Notes Pricing			99.954%
Debt Instrument, Interest Rate, Stated Percentage			2.90%		2.90%		2.90%
Debt Instrument, Interest Rate, Effective Percentage	[1]		2.984%		2.984%		2.984%
Proceeds from unsecured senior notes			$ 693,800
Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 5.708% [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.625%
Repayments of Unsecured Debt		$ 740,700
Debt Instrument, Increase, Accrued Interest		$ 13,500
Debt Instrument, Redemption Price, Percentage		103.90%
Loss from early extinguishment of debt		$ (28,000)
Redemption Premium		27,300
Debt Instrument, Face Amount		$ 700,000
[1] Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.

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